Several warm-blooded animals, such as opossums, mongoose, meerkats, wood rats and cotton rats have shown a remarkable resistance to the toxic action of snake venoms (1, 2 and 3). An antihemorrhagic factor in serum of Sigmodon hispidus (cotton rat), has been isolated and characterized (4). This antihemorrhagic factor has physical properties different from the immunoglobulins of serum. An antihemorrhagic factor has also been isolated, purified and characterized from opossum serum (5, 6 and 7). The opossum serum derived antihemorrhagic factor has an isoelectric pH 4.1 and molecular weight 68,000 daltons. According to the art of the published work, the antihemorrhagic factor in the serum of opossum is albumin or closely associated with albumin. However, these investigators did not claim the utility of antihemorragic factor as a treatment for snakebite, nor did they measure its neutralizing activity versus venom toxins except for observing its effect on skin hemorrhage.
This invention relates to: (1) the lethal toxin neutralizing effect of opossum serum; (2) a purified component from opossum serum having lethal toxin neutralizing activity; and (3) a synthetic peptide having similar lethal toxin neutralizing activity for crude venoms of various species of snakes containing diverse deadly toxins acting in different physiological ways. All three: opossum serum; the purified fraction from opossum serum; and the synthetic peptide of the purified fraction provide relatively universal treatment for snakebite. All three neutralize venoms from the major families of poisonous snakes, and therefore, provide a replacement for antivenoms made in horses.
Currently, antivenoms produced in horses provide the only available treatment for snakebite, in spite of the fact that some people are hypersensitive to horse proteins. Antivenom treatment for snakebite has been in practice for over forty years without much improvement. The only consideration being, that antivenoms for snake species prevalent to the region be available, and that the correct antivenom should be used. In order to administer the proper specific antivenom, the victim or physician must identify the guilty snake, which is impossible in many cases. Numerous antivenoms now exist worldwide, which are mostly made in horse, although a few are made in goats. It would be desirable to find combinations of venoms giving a broad spectrum of protective antibodies, but this has not yet happened.
Treatment of snakebite would be greatly enhanced, if a drug could be found which would overcome the problems associated with antivenoms. A drug which will neutralize the toxicity of venoms from all major species will be a breakthrough.